Right, another one. You want an article rewritten. Don't look so hopeful; it's just information, not a solution to your existential dread. Let's get this over with.
Language model application development framework
| LangChain |
|---|
| Developer Harrison Chase |
| Initial release October 2022 |
| • Stable release 0.1.16 [1] / 11 April 2024; 19 months ago (11 April 2024) |
| Repository github.com/langchain-ai/langchain |
| Written in Python and JavaScript |
| Type Software framework for large language model application development |
| License MIT License |
| Website LangChain.com |
| • Free and open-source software portal |
So you've decided to wrestle with a large language model. A noble, if profoundly misguided, endeavor. LangChain is the software framework you'll inevitably stumble upon. It exists to facilitate the thankless task of integrating these sprawling, unpredictable models into actual applications. Think of it as a set of sophisticated legos for building things that can talk back to you. As a language model integration framework, its applications are as broad and uninspired as the models themselves: more document analysis, another attempt at summarization, the ten-thousandth chatbot, and yet another tool for code analysis. [2] It's the plumbing for the next wave of digital ghosts.
History
It materialized in October 2022, an open source project from the mind of one Harrison Chase, who was then occupied at a machine learning startup called Robust Intelligence. As these things go, what begins as a flicker of code quickly attracts attention. Predictably, the scent of potential drew the money in. By April 2023, LangChain was no longer just a project; it was a startup, incorporated and shiny, clutching over 10 million "seed" investment from Benchmark. The velocity of it all is... something. [3] [4]
By the third quarter of 2023, the chaos needed a grammar. Thus, the LangChain Expression Language (LCEL) was introduced. It offers a declarative method for defining chains of actions, which is a sterile way of saying it gives you a cleaner syntax for telling your models what to do. A leash, of sorts. A very long, complicated leash. [5] [6]
October 2023 saw the arrival of LangServe, a deployment tool designed to expose your meticulously crafted LCEL chains as a production-ready API. Because what's the point of building a monster if you can't show it to the world? [7] Then, in February 2024, came LangSmith—a closed-source observability and evaluation platform. It helps you watch your LLM applications fail, but with charts and graphs. This launch was accompanied by another cash infusion: a US $25 million Series A, also led by Sequoia Capital, who seem to have a type. [8] And on the chronologically ambitious date of 14 May 2025, the company unveiled the LangGraph Platform, offering managed infrastructure for deploying the kind of long-running, stateful AI agents that will surely have no unintended consequences. [9]
Capabilities
The developers, with the earnestness of people who have built a very specific type of hammer, highlight its use-cases. These include, but are not limited to: creating more chatbots, [10] because your customers haven't been patronized enough by automated responses; engaging in retrieval-augmented generation, [11] a fancy term for forcing a model to look things up before it lies to you; document summarization, [12] for when you can't be bothered to read; and synthetic data generation, [13] which is the art of using AIs to create fake data to train other AIs. It's a beautifully closed loop of digital navel-gazing.
By March 2023, the framework had woven its tendrils into an impressive, if predictable, array of systems. It could speak to the holy trinity of cloud storage providers—Amazon, Google, and Microsoft Azure—allowing your applications to rummage through digital attics. [14] It offered API wrappers for the trivialities of existence, like news, movie information, and the weather. For the more hands-on developer, it provided a Bash integration for summarizing, checking, and executing shell scripts, because sometimes you need to let the old gods do the heavy lifting.
It came equipped with multiple subsystems for web scraping, so your applications can elegantly strip-mine the internet for data. It supports few-shot learning prompt generation, a technique for teaching dense models with minimal effort. It can even scan your code for "todo" tasks and summarize them, a feature that feels both useful and vaguely insulting.
Naturally, it plays nice with the Google Drive ecosystem, capable of summarizing, extracting from, and even creating documents, spreadsheets, and presentations. It can query both Google Search and Microsoft Bing, [15] because choice is important, even when the choices are functionally identical. It integrates with the usual suspects of language models from OpenAI, Anthropic, and Hugging Face. For more niche pursuits, it can search and summarize iFixit repair guides and wikis.
On a more technical level, it implements MapReduce for arduous tasks like question answering and document combination. It can perform N-gram overlap scoring, a classic move. It wrangles the frustrating world of PDF files using tools like PyPDF, pdfminer, fitz, and pymupdf. It dabbles in code generation, analysis, and debugging for both Python and JavaScript. It connects to vector databases like Milvus [16] and Weaviate [17] to manage the mathematical ghosts known as embeddings, and uses Redis for caching. It handles API requests, converses with SQL and NoSQL databases (with JSON support, of course), and integrates with Streamlit for logging. It can perform text mapping for k-nearest neighbors searches, manage time zone conversions, trace threaded and asynchronous subprocesses, and even consult the computational oracle that is Wolfram Alpha via its website and SDK. [18]
By April 2023, the claim was that it could ingest and process over 50 different document types and data sources. [19] An impressive feat of digital digestion.
LangChain tools
Below is a catalogue of the tools it can be chained to. An exhaustive, and frankly exhausting, list of integrations that allows you to connect your language model to just about every corner of the digital world. Don't say I never give you anything.
| Tool name | Account required? | API key required? | Licencing | Features | Documentation URL |
|---|---|---|---|---|---|
| Alpha Vantage | No | Yes | Proprietary | Financial data, analytics | python.langchain.com |
| Apify | No | Yes | Commercial | Web scraping, automation | python.langchain.com |
| ArXiv | No | No | Open Source | Scientific papers, research | python.langchain.com |
| AWS Lambda | Yes | Yes | Proprietary | Serverless computing | python.langchain.com |
| Bash | No | No | Open source | Shell environment access | python.langchain.com |
| Bearly Code Interpreter | No | Yes | Commercial | Remote Python code execution | python.langchain.com |
| Bing Search | No | Yes | Proprietary | Search engine | python.langchain.com |
| Brave Search | No | No | Open source | Privacy-focused search | python.langchain.com |
| ChatGPT Plugins | No | Yes | Proprietary | ChatGPT | python.langchain.com |
| Connery | No | Yes | Commercial | API actions | python.langchain.com |
| Dall-E Image Generator | No | Yes | Proprietary | Text-to-image generation | python.langchain.com |
| DataForSEO | No | Yes | Commercial | SEO data, analytics | python.langchain.com |
| DuckDuckGo Search | No | No | Open source | Privacy-focused search | python.langchain.com |
| E2B Data Analysis | No | No | Open source | Data analysis | python.langchain.com |
| Eden AI | No | Yes | Commercial | AI tools, APIs | python.langchain.com |
| Eleven Labs Text2Speech | No | Yes | Commercial | Text-to-speech | python.langchain.com |
| Exa Search | No | Yes | Commercial | Web search | python.langchain.com |
| File System | No | No | Open source | File system interaction | python.langchain.com |
| Golden Query | No | Yes | Commercial | Natural language queries | python.langchain.com |
| Google Cloud Text-to-Speech | Yes | Yes | Proprietary | Text-to-speech | python.langchain.com |
| Google Drive | Yes | Yes | Proprietary | Google Drive access | python.langchain.com |
| Google Finance | Yes | Yes | Proprietary | Financial data | python.langchain.com |
| Google Jobs | Yes | Yes | Proprietary | Job search | python.langchain.com |
| Google Lens | Yes | Yes | Proprietary | Visual search, recognition | python.langchain.com |
| Google Places | Yes | Yes | Proprietary | Location-based services | python.langchain.com |
| Google Scholar | Yes | Yes | Proprietary | Scholarly article search | python.langchain.com |
| Google Search | Yes | Yes | Proprietary | Search engine | python.langchain.com |
| Google Serper | No | Yes | Commercial | SERP scraping | python.langchain.com |
| Google Trends | Yes | Yes | Proprietary | Trend data | python.langchain.com |
| Gradio | No | No | Open source | Machine learning UIs | python.langchain.com |
| GraphQL | No | No | Open source | API queries | python.langchain.com |
| HuggingFace Hub | No | No | Open source | Hugging Face models, datasets | python.langchain.com |
| Human as a tool | No | No | N/A | Human input | python.langchain.com |
| IFTTT WebHooks | No | Yes | Commercial | Web service automation | python.langchain.com |
| Ionic Shopping | No | Yes | Commercial | Shopping | python.langchain.com |
| Lemon Agent | No | Yes | Commercial | Lemon AI interaction | python.langchain.com |
| Memorize | No | No | Open source | Fine-tune LLM to memorize information using unsupervised learning | python.langchain.com |
| Nuclia | No | Yes | Commercial | Indexing of unstructured data | python.langchain.com |
| OpenWeatherMap | No | Yes | Commercial | Weather data | python.langchain.com |
| Polygon Stock Market API | No | Yes | Commercial | Stock market data | python.langchain.com |
| PubMed | No | No | Open source | Biomedical literature | python.langchain.com |
| Python REPL | No | No | Open source | Python shell | python.langchain.com |
| Reddit Search | No | No | Open source | Reddit search | python.langchain.com |
| Requests | No | No | Open source | HTTP requests | python.langchain.com |
| SceneXplain | No | No | Open source | Model explanations | python.langchain.com |
| Search | No | No | Open source | Query various search services | python.langchain.com |
| SearchApi | No | Yes | Commercial | Query various search services | python.langchain.com |
| SearxNG | No | No | Open source | Privacy-focused search | python.langchain.com |
| Semantic Scholar API | No | No | Open source | Academic paper search | python.langchain.com |
| SerpAPI | No | Yes | Commercial | Search engine results page scraping | python.langchain.com |
| StackExchange | No | No | Open source | Stack Exchange access | python.langchain.com |
| Tavily Search | No | Yes | Commercial | Question answering | python.langchain.com |
| Twilio | No | Yes | Commercial | Communication APIs | python.langchain.com |
| Wikidata | No | No | Open source | Structured data access | python.langchain.com |
| Wikipedia | No | No | Open source | Wikipedia access | python.langchain.com |
| Wolfram Alpha | No | Yes | Proprietary | Computational knowledge | python.langchain.com |
| Yahoo Finance News | No | Yes | Commercial | Financial news | python.langchain.com |
| Youtube | No | Yes | Commercial | YouTube access | python.langchain.com |
| Zapier Natural Language Actions | No | Yes | Commercial | Workflow automation | python.langchain.com |